8800GT voltage mods

[renzokuken]

HitandRun,

So on the other end of those two cables is a 100K VR correct?

[HitandRun]

HitandRun,

So on the other end of those two cables is a 100K VR correct?

Yes sir that's correct!

[renzokuken]

Thanks!

[renzokuken]

OK, here's a thought. If I pencil that OCP related resistor, thus lowering the resistance, will it increase the OCP limit?


Edit: What about if I were to remove the resistor entirely?

[largon]

If I pencil that OCP related resistor, thus lowering the resistance, will it increase the OCP limit?

It doesn't matter what you use to lower the resistance. VR, pencil, etc.

What about if I were to remove the resistor entirely?

That would increase the resistance between the solder pads the resistor is soldered onto. You need to lower the resistance.

[renzokuken]

That would increase the resistance between the solder pads the resistor is soldered onto. You need to lower the resistance.

Ah yes, that is so obvious now. Sorry for asking such a stupid question

[gugle]

not sure about pencil mod but mem chip is on other side of the card at the rear


vmod here


ecs 8800gt has been cover'd in thread

what must be done?
how to connect?

[EvoCarlos]

what must be done?
how to connect?

for vcore 100k vr from fb to gnd


dont bother with mem in tests it show no improvment with less or more volts cause of quadama chips (1000mhz @2.05v stock)

you could always alter the vid from 1.1v stock to 1.4v this also move ovp/ocp further up the volt range
i did 0 0 1 1 0 =1.400v
before

after

[gugle]

thanks, my memory is Hynix, it is only 730mhz =(

[EvoCarlos]

thanks, my memory is Hynix, it is only 730mhz =(

oh cool
not sure what the hinix will do if the good chips unlike the quadamas then vmod can be done but i dont know how good they are

[CryptiK]

I've been a bit slow on the uptake and quite busy, so I just modded my card tonight. I only did the vGPU mod and used a 500 Ohm VR. Previously crysis stable clocks were 702/1728/900 and now running 1.15v idle / 1.20v load it's crysis stable at 756/1782/900 (my ram is stock 900 and I don't think I'll increase it lest I burn out the controller). It got me a couple more FPS in the game and increased my 3DM 06 score by around 300 points. I could probably get 771/1832/900 stable but I'd need around 1.22 - 1.23v for that and I'm not sure the cards PWM and core temps would remain decent if I did that.

As I'm on air using a Zalman VF-830 temps are 49*C idle / 75*C load. The PWM is getting quite hot, so I intend to put a few ram sinks I have lying around on the mosfets and other components.

Thanks for the work you guys have put in to develop this.

EDIT - has anyone been running their ram at ~1000 MHz for a decent length of time without any issues?

[largon]

The memory (Qimonda) on my card is and has been stable at 1044MHz for almost a year now. With reverse mod - vMEM @ ~1.95v.

[CryptiK]

Nice, what kind of card do you have?

I wonder why there was all the talk (from a supposed reputable source too) that 1000 MHz + will damage the card in a short time?

Also, what vGPU are you running 24/7? What kind of extra cooling for the PWM are you using? I'd be interested to know since it's lived so long.

[CL3P20]

I am really interested in this mod..as I am still trying to figure out a mod for the EVGA dual-slot 9600GSO. I has the same layout pictured above..and uses the RT8802A.. yet it has SMR's in the mod location..? Any ideas..HELP!!

*I removed some of the resistors, for a VID increase [according to the RT8802A datasheet]..and no change!

[largon]

CryptiK,
It's a plain-jane Asus 8800GTS 512MB.
GPU is watercooled and runs at 1.36v. Memory chips are bare, there's a 80mm fan @ 5v blowing on the RAM and the alu sink on the vGPU mosfets. Too bad the card has just lately started to trip no matter what freqs, it's kinda stable for hours of Crysis but might crash even at stock.

CL3P20,
Measure resistance between pin#4 of RT8802A, solder a VR rated 20× the measured value between pin#4 and ground. Tune down to increase voltage.

[CryptiK]

Thanks or the info. I was under the impression the GT's were the only cards susceptible to the memory controller burning out at 1000 MHz+ and that the GTS's were designed slightly differently and were fine? Almost all the GT's were released with mem speeds lower than 1000 MHz and the GTS's all had mem speeds above 1000 MHz.

[CL3P20]

@ Largon - Thanks a bunch.. I will perform the mod this weekend and post results. If you are correct, a lot of people have anxiously awaited this mod.. I will buy you a cake, so long as I have working GPUv.

[largon]

CryptiK,
I doubt there's any difference in GT and GTS for what comes to the memory controller or anything related to memory as the GPUs are the same just GT is shader-crippled - GDDR and memory vregs are the same. Even the PCB is identical. And as such I don't think memory OC'ing on GT is any more "dangereous" than on GTS. Infact, I haven't seen any reports of suspicious memory deaths...

[CryptiK]

After looking at pics of both boards they do appear to be identical. What do you think the issue is with yours (crashing even at stock now)?

With 1.225v load my card appears to be stable at 756/1836/900. Temps are quite high though, in 27*C ambient its hitting 78*C in crysis. I put sinks on the GPU phase mosfets, they get hot but I can leave my finger on them, so they're probably close to 45 - 50*C.

It seems core increases give me the biggest gain in 3DM06, 18MHz core increase gives 108 marks increase, and 54MHz shader increase gives me 63 marks increase.

[basco]

hi all!
it took me nearly 2 days to read the thread,but i am not man enough to try it.
its richtek RT8802A,but if i look on their site i got the layout and then a typical layout and its different.one time fb is 3rd and then 4th pin?
if someone could give me an idea-very appreciate your help

[largon]

basco,
Written guide in post #1190 applies to your card too.

[basco]

thanks largon for your quick answer.

but i am too silly to find fb-leg?

is this ok?

[basco]

if i look at post 1189 above and on richtek site i could not figure out where fb is.-they have a pin-layout and one typical layout-and marked place above is my guess.
pins are so small that i have to follow the route of fb-leg and do the mod there?-is my thinking ok?

thanks for your time

[largon]

The dot marks pin#1 on the chip. So in your pic pin#1 would be on the first from left on bottom row. #4 is 4th from left.


(pic from datasheet is rotated 90° clockwise compared to chip in your pic)

[yiancar]

here you go mate